The present invention relates to a magnetic resonance imaging apparatus, and more particularly to an apparatus for conducting magnetic resonance imaging with spins within a subject brought to an SSFP (steady state free precession) state.
One conventional technique for conducting magnetic resonance imaging is a method of conducting magnetic resonance imaging with spins within a subject brought to an SSFP state. The method produces an image based on a sum of or a difference between echo data acquired with an RF (radio frequency) pulse having an invariant phase and echo data acquired with an RF pulse having a phase alternating between 0 and π (see, for example, Patent Document 1).
Conventional techniques for suppressing fat signals in magnetic resonance imaging include a method employing a fat suppression pulse (see, for example, Non-patent Document 1), and a method employing FEMR (fluctuating equilibrium magnetic resonance) (see, for example, Non-patent Document 2).                [Patent Document 1]                    Japanese Patent No. 2398329 (pages 1-9, FIGS. 1-5)                        [Non-patent Document 1]                    Klaus Scheffler, et al., “Magnetization Preparation During the Steady State: Fat-saturated 3D TrueFISP,” Magnetic Resonance in Medicine, 45:1075-1080 (2001).                        [Non-patent Document 2]                    Shreyas S. Vasanawala, et al., “Fluctuating Equilibrium MRI,” Magnetic Resonance in Medicine, 42: 1075-1080 (1999).                        
Images captured by the conventional techniques and by FEMR exhibit banding artifacts when the static magnetic field strength distribution is inhomogeneous.
Fat suppression by the aforementioned fat suppression pulses is unsuitable for imaging in the SSFP state because the steady state is disturbed.